


Only an Ocean Between Us

by uwa-so-frisk (disillusionist9)



Series: Undertale: SINonymous [4]
Category: Undertale (Video Game)
Genre: Established Relationship, F/F, Fluff, Fluff and Smut, Mutual Pining, Phone Sex, Post-Undertale Pacifist Route, Reader Is Not Chara, Reader Is Not Frisk, Reader-Insert, Sex, Smut, Soul Bond, Soul Sex, Undertale Monsters on the Surface, Undyne Swearing, Voyeurism, reader is female
Language: English
Status: Completed
Published: 2018-02-11
Updated: 2018-02-11
Packaged: 2019-03-16 20:45:30
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,101
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13644114
Author URL: https://archiveofourown.org/users/disillusionist9/pseuds/uwa-so-frisk
Summary: You and your wife, Undyne, are settling nicely in your new home on the surface, but duty calls, and she has to take an extended trip with the Dreemurrs across the ocean on a diplomatic mission. Work on the Core has to be completed, so you and Sans stay behind while most of your family goes overseas. You wake up suddenly in the middle of the night a week after they left while Sans is working overnight in the Underground, and when you feel the hand grab your leg again, you decide you need to call your wife to see what's going on.





	Only an Ocean Between Us

At first you aren’t sure why you woke up in the middle of the night.

There aren’t any unusual noises in your home, just the regular sounds of the radiator kicking off, the fridge running downstairs, and the slight sound of cars passing by. You’d only lived here for a few months, but you wanted so badly for it to really be your home, you’d gotten accustomed to it faster than you ever had to a new place. The people living here certainly helped. 

But it couldn’t be Papyrus that woke you up - the skeleton is still traveling with the ambassador and royal family on a diplomatic missing. Sans is taking his overnight shift in the Core while you sleep to get ready for your turn in the Underground. As you sit up in your half-empty bed wondering what woke you, it happens again.

A soft pressure rubs against your thigh in the shape of a hand you’re very familiar with, and you are so surprised that you nearly scream. At least there’s no one home to hear you.

Leaping out of the bed, you tear away the covers, the duvet flopping to the floor unceremoniously. There’s nothing there that could possibly have felt exactly like your wife’s hand along your leg. As you reach over to flip on the bedside lamp, you feel it again, and the sensation nearly sends you out of your skin. Your body recognizes that familiar pleasure but your mind is having a hard time catching up to exactly what’s happening.

Face down on your nightstand, your phone sits quietly. You snatch it up and groan when you see the time. Half past four in the morning. You’re definitely not getting back to sleep, and it might still be too early to make a phone call. Or late? Your mind is mush when you first wake up so you sit on the edge of the bed, and unlock your phone to open your clock app. 

A little star floats next to the JST time zone slot. Closer to ten at night for your wife, then, and the others on the diplomatic trip to Tokyo. Would that be too late to talk to her? You rub your eyes as you try to remember what the delegation had on their plates for today. What day was it, anyway?

The ghostly hand feeling starts up again, sending shivers down your spine and between your...no that’s the ghost hand moving closer to the apex of your thighs.

You grip the sheet next to you with your free hand and take a deep breath. The feeling is a move that your wife would sometimes use to gently initiate sex in the middle of the night, a move you recognize and is  _ very _ welcome after more than a week of not seeing or touching your bond-mate. But it feels wrong! She’s not here!

Fuck it. You’re calling her.

The other line rings three times before she answers.

“Hello-”

“Something’s happening to me and it’s freaking me out,” you say in a rush, cutting off Undyne’s greeting before she can get more than the first word out. There’s surprised silence on the other end but now that the words have started you can’t stop them. “I woke up like a half an hour ago, I felt something, and I don’t know. I just-”

“Woah, babe, breathe,” Undyne says, her voice coming in clearer after a moment. She’d sounded muffled before for some reason. “What’s happening? Talk to me. Do you need me to get Sans over there, or Grillby?”

You shake your head, forgetting she can’t see you, and blurt out, “No, no, it’s not that bad. I don’t think.” You take a deep breath in, the first real rush of oxygen you’ve had in several minutes now.

“Then talk to me babe.”

The sound of her voice, even though you just talked to her before you went to bed, sends a flood of calm through you. You’ve known her for almost five years now, but this level of connection is still very new. The bond between your Souls was created only a few months ago and this is the longest you’ve been without her since then. Now that you have her on the phone you’re not sure how to start.

“Um,” you say, clearing your throat and taking a sip from the water bottle you keep by your bed, “so, I don’t think I’m in danger or anything, I’ll start with that. I just...something woke me up and freaked me out.”

You hear rustling on the other end and imagine you woke your bond-mate up, and instantly start to feel guilty. With the time zone change and the full schedule, you know she’s been so busy.

“Okay, what happened?” Undyne pushes. Her voice is gentle, but direct.

“I thought I felt your hand on my leg.” The words leave your mouth in a rush and there’s another silence on the other side of the phone.

“Hey, you wanna switch to video chat?”

Undyne’s question catches you off guard. “Right now? But I just woke up, I look awful-”

“Babe. Please?”

“Ugh,” you huff, pulling the phone from your face, setting it on a charging dock, and switching call to a video stream. It’s blurry since the room is still pretty dark on you side, despite the lamp in front of you. Your hair is a mess and you look washed out, but you ignore the little window showing your face to focus on your wife’s.

“God, you’re beautiful,” you mutter as her blue skin and red hair fill the camera for a second before she pulls it back to look at you.

A toothy grin fills her face. “Not as beautiful as my mate. Good...morning, good looking?”

“Yeah, it’s like five in the morning here,” you say, confirming her question. 

One of your elbows rests on the nightstand as you gaze at her. All the anxiety and energy you felt first waking up ebbs away as you look at her. Her scaly skin shimmers in the flourescent lights of her suite’s bathroom. Dressed for bed, she’s wrapped in what looks like a sinfully soft bathrobe with the hotel’s logo sewn into the pocket, red hair bright against the fabric. She left it out of her ponytail to sleep, and you feel your hands tingle, wishing you could run your fingers through it.

How in the world had you gotten so lucky?

“So you felt my hand on your leg?”

Her grin is wider when you focus again. Damn, you spaced out. She never minds, though. Undyne is nothing if not confident, one of the many, many reasons you fell in love with her at the start.

“That’s what it felt like,” you say as you suppress a yawn. “Weirdest shit ever and it spooked me.”

Undyne tilts her head a little and her single visible eye blinks slowly. She looks perky talking to you, which warms you to the core of your Soul, but there’s still a shade of exhaustion over her face that’s hard to miss even though a shaky video connection. A light tint of purple runs over her cheekbones in a blush and she chuckles a little. 

“Heh, didn’t know you’d feel that, actually,” she says.

You lose another battle in the yawn war, and almost choke when you ask, “What?”

“I, uh, I miss you. You know? So I was…” Undyne trails off, but her ferocity doesn’t take long to come back after the moment of shyness. “I miss the way you touch me. The way you feel sleeping next to me, the sound of your voice, the sound of your Soul, everything. I miss you, you big NERD.”

“Oh, god, I miss you, too,” you say. 

Out of nowhere you can feel the slightly tight feeling of tears in your throat. You don’t want to cry now! Undyne has seen you at your lowest, but she’s across the ocean on an important mission, and doesn’t need to worry about her blubbering spouse back home. Not for the first time you wish you’d been able to tag along with the group, but with things getting close to a solution with your work on the Core with Sans and Alphys, you couldn’t leave. You’re able to keep it together but you get the impression Undyne can tell you’re upset anyway.

“______, I love you and can’t wait to be home again,” Undyne says. Her bottom lip goes in between her teeth again and the weakness in your knees at the sight would make you stumble if you were standing. Fuck, that’s hot. “That’s why I was thinking about you  _ a lot _ tonight.”

Through the haze of your lust at the image she’s giving you, you catch her meaning. Mouth slack, you look up from those fierce teeth teasing the lips you want to be kissing, and meet her gaze. A shimmer ripples over the screen and you curse the unfairness of the technology gods right now. All you want is an unobstructed view of your wife.

The two of you have had your share of, ah, adventures, especially when you first started dating and were navigating the waters between the differences of monster and human intimacy. You’d found some  _ very  _ delicious similarities, however, in your mate. The few other monsters you’d bedded before her were made entirely of magic and had different expectations than what you were used to. But Undyne is a mixture of magic, flesh, and something she calls  _ meer _ , a word that resembled the German translation of “sea”, and binds the magic and flesh together to create her body. 

Oh, you had some  _ wonderful _ physical similarities. The first time you’d gotten each other out of your pants there was a mutual feeling of relief at the familiar makeup between your legs.

Some of those early adventures included exactly what she was referencing now, except it usually involved her calling you in the middle of the night from whatever location she was working, breathless, your name on her lips as she worked herself closer to-

“Holy shit,” you whisper, interrupting your own heated thought process. “So...what does that have to do with…”

Undyne blinks slowly and releases her lip from her teeth. “I thought about you when I was touching myself.”

If you were wearing panties, instead of a loose pair of sleep pants, they’d be soaked. Your hand is gripping your thigh as tightly as the phantom sensation you’d woken to, and if what Undyne was telling you was possible then you had  _ so  _ many questions. 

As a scientist, it’s only right for you to test a few hypotheses, right?

Right.

“That really was your hand, then,” you say in wonder. “Why, I mean, how? How?”

Undyne sounds like her breathing is starting to pick up when she answers, “Our bond. I haven’t been away from you since we bonded and I didn’t know if it would work, so I decided to just...test it out.”

You feel like you should be miffed at her for not saying something. And, how had you missed something like this in your research before binding your soul to her? You’d gone over so many ancient texts to make sure this would work, and you wouldn’t somehow hurt or weaken the strong fish by binding to her. 

“Stars, move your hand a little higher, you’re killing me, babe.” Undyne is definitely losing her breath by the tone of her voice now.

Out of reflex at the near commanding sound of her voice, your hand gripping your thigh moves higher towards your aching center, your thumb brushing your lower lips in your haste to obey her. 

A little clattering sound reverberates from the other end of the line as Undyne drops her phone onto the hand towel set next to the sink. You can see the bristles of her toothbrush instead of her face for a moment. When she picks it back up again, she’s walking through her suite out of the bathroom and back into the bedroom, the purple flush on her face darkened and spreading to her neck and frills. 

Your hand is still very close to your center but you’d brought it back at the intensity of her reaction.

“I don’t know how this is working but I don’t want you to stop,” you say.

Undyne settles her phone on the nightstand next to her, too, and blinks, her pupil dilating slightly wider as she looks at you. There’s nothing in this world that makes you feel sexier than the way she looks at you.

“Good. Because  _ fuck _ I need you so badly right now.” Her voice is throaty and changing to a tone that makes you respond immediately.

Undyne, Captain of the Royal Guard, has your undivided attention.

“I want you to lean back on the bed, babe,” she says, eye still focused completely on you even as she starts to undo the knot of her bathrobe.

You obligue immediately, making sure you can still see her face and she can see as much of you as the front facing camera allows. At this angle you can see how her other hand moves to trace a finger along her collarbone, the mimicry of that touch running along yours. Your hands are fisted in the hem of your shirt, unsure whether or not you’re allowed to touch yourself yet. Undyne didn’t always use this sort of power play in the bedroom, preferring a mutual push and pull of domination that you really enjoyed. But sometimes, like now, she would take control. And you let her.

The bathrobe is loose and partially open now. You can see where she isn’t wearing anything on top, your imagination left to fill in the rest of the blanks. She licks her lips and says, “Shirt first.”

Hands already fisted in the hem, you pull it over your head without getting off your back, your arms crossing in front of you. There’s an intake of breath through your phone speaker as your back arches to help get the shirt off, pushing your breasts up into her line of sight easily. The chill of the air rushes over your exposed chest, lifting your nipples to attention. Nights like this you’d gladly be spooned by your slightly cold-blooded wife to provide the warmth she needs, but this is a welcome alternative.

Slightly propped up on a pillow, you turn your head to look at her again, chest starting to rise and fall more quickly as your breathing picked up. You know your hair is a mess, but all you can focus on right now is the way she looks at you.

Undyne’s hand absently keeps stroking her collarbone, spending extra time pressing her fingertips into her sternum where her Soul rests underneath. Each brush is equal parts heaven and torture for you. Between the slight delay in the video feed and what you feel through your bond, your senses are on fire.

“Beautiful,” she says as she stares. “Now, your shorts.”

You whine a little in protest. “But-”

“Now.”

Your hands start to push them down over your hips, past your thighs, before lifting your legs to toss them away. It’s ghastly unfair that you’re completely exposed to her now, and you still only get teasing glimpses of the patterns of her scales under her robe. She looks so single-minded right now that it almost makes your frustration worth it. 

“I want to see you, too,” you say.

Undyne looks nearly startled at the sound of your voice. Pausing her unabashed admiration of what she can see, she looks up to your face, the purple blush from her magical ‘blood’ rushing up to her cheeks beautiful in the low light of her hotel room. 

Her grin goes from slack to primal in a flash. You don’t always vocalize exactly what you want when she’s like this, preferring to allow her to call the shots, but it’s been too long and the teasing feeling on your bond is making the pressure coil in your stomach at record speed. 

“As the lady wishes,” she replies, shrugging out of her robe and throwing it out of your sight.

You suck in a breath of air, like it’s the first real breath you’ve taken since you kissed her goodbye at the airport. In the slightly yellow light of her room, the edges of her scales are limned in gold, and again you curse the ocean between you. If she were in your bed you would be able to see the way each scale smooths harmoniously into its neighbor, and how each one catches the light in a different way. Your fingers itch to run over them.

“I wish I could touch you,” you say, your hand moving towards the phone’s screen.

The look on her face is hungry, but her fingers move towards her camera as well with gentle longing. The black polish on her nails glints like her scales. 

“What would you do?” she asks, voice growing husky. Her fingers still fill half the screen.

“I would-”

“No. Don’t tell me. Show me.”

The dark blue Soul inside of you does a little flip in time with the butterflies in your stomach. Without speaking, you pull your hands away from the screen and turn so you’re on your side facing her. Slowly, you take your top hand up to your breast and run your thumb over your cold-pinched nipple, using the other fingers to cup yourself. A low sigh leaves your lips at the relief that small touch gives you, and it’s mirrored through the connection on your phone.

Undyne holds her hand over her sternum, between her breasts to clutch against the spot housing her Soul. She explained before that this spot is just as sensitive for her as some of your own erogenous zones. You received pleasure from your Soul as well, but not nearly as much as she does, so watching her touch herself here is the same for you as her watching you now.

Extremely hot.

It’s distracting, almost to feel the pleasure you’re giving yourself reflected back through your bond from Undyne. The two of you had felt this almost every time you touched each other after your bonding ceremony, no matter the intention of the touches. A hand along the back of your neck as you made coffee in the morning felt the same as a whispered  _ I love you _ against your neck. A hug not only wrapped her arms around you, but the feeling of connection and loyalty tangibly moving across her skin to your Soul. This was not so different, then, though the distance was a variation on a familiar theme.

“Yesss,” Undyne hisses through her teeth. 

Her response to you dipping your hand lower towards your slit is exactly what you wanted. The connection starts to get a bit blurry, but you know that’s because she dragged her Soul out so she could mimic the pleasure you were giving yourself. Monster souls reject human-made cameras as much as teenagers sometimes refuse to get their picture taken. It constantly flits in and out of focus, forcing the lense to work double time as it decides what to focus on. You can see just a slip of the white color of the upside down heart beneath her hand, but not entirely. 

Without preamble, you slip your hand down to your aching core, and watch closely at the way Undyne’s back arches upwards. Her head pressed down into her pillows, you can just make out the way her lips part, her chest heaves in pants, and the red of her hair frames the entire image.

She’s beautiful like this.

Slowly you work yourself up by watching her. After a minute or two she gets more control of herself and sits up again, eye blazing with intent. Her posture is predatory, leaning towards the camera with her loose hair spilling around her face and fins flared on the sides of her head. One hand props her up while the other traces slow patterns on the Soul you can’t see and wish you could.

“That’s it, baby,” she says, voice almost a growl as she stares at you. “Tease yourself a little, now, don’t need you coming just yet.”

You would cry from frustration if her words weren’t laced with lustful promise. The hand between your thighs slows to just circle your clit, waiting for her next command. By now your thighs are trembling, the touches pushing you further towards the finish line. With the reflection of your pleasure back and forth, and the way you’ve been unable to take care of yourself since you last saw her, your body is buzzing with the desire to come. 

Undyne pushes her Soul back into her chest slowly, using that hand to move out of your range of vision. You want to ask what she has planned but when another hand joins your own between your thighs, you exclaim in pleased surprise.

“Oh,  _ fuck _ yes,” you gasp, hips starting to buck into the feeling of their own accord. 

If you look down you can’t see her there, but the way she’s working herself out of your line of sight is apparent. Part of you had hoped this would work back and forth between you, if her other touches on herself were any indication.

Breathing heavily, Undyne gives you the most self-satisfied smirk even as her shoulders start to shake. She’s clearly feeling the same as you are as you fist one hand into the sheets beside you and you buck your hips into the feeling of her hand. 

“This...oh,  _ stars, _ this is crazy and amazing and -  _ holy shit don’t stop _ !”

With a short chuckle, Undyne answers by swiping a thumb over herself again before adding a finger a few knuckles deep.

If you weren’t already so far gone from the reflected stimulation, you think you would have been embarrassed at how fast this “experiment” made you come against her ghostly hand. There’s a muffled ‘ _ fuck _ !’ on the other end of the line that tells you Undyne wasn’t expecting that, either. You’re so glad no one is home to hear the almost sobbing cry of ecstasy on your end, but your sex-hazed brain reminds you that Undyne is likely in a room that neighbors the king, or Papyrus, or heaven-forbid  _ Frisk _ .

“Motherfucker,” Undyne gasps into the pillow she has shoved against her face. “That...worked better than I expected it to.”

A slightly hysterical bubble of laughter rises in your throat. Your thighs are still trembling slightly. “You’re telling  _ me _ , holy shit, babe. I wonder if it was because of the way you were touching your Soul, because I don’t think I’ve ever come that fast.”

“Nerd,” she says affectionately. “Science in the bedroom again.”

“Don’t deny it, you love it.”

“I love  _ you _ .”

You gaze at her softly and return the affection. Times like this you wish you could show her how beautiful she is to you. Her hair is pushed completely to the side as she rests her cheek against the pillow she didn’t destroy with a tremendous bite while coming. Pupil still dilated, her visible eye watches you with obvious fondness that would make you squirm in near-embarrassment if you weren’t doing the same to her, too. 

As both of you catch your breath, the moment is interrupted by your first alarm, an obnoxious sound filling the room and startling you both. You switch it off quickly and almost drop your phone in the process. Undyne is chuckling on her side of the line when you bring the image back up. 

Her eye blinks slowly and she yawns. “Time to get up?” she asks wickedly.

You stick your tongue out at her. “Yeah. I need to switch shifts with Sans in -” you check the time “-two hours.”

Undyne’s frill picks up in interest, some of her tiredness melting away as she opens her mouth to say, “Two hours? That means we have time to try that again, yeah?”

You bite your lip at her enthusiasm. Those two hours are strategically to allow you time to get up, eat, pack lunch, shower, anything you need to do before Sans comes to shortcut you into the Underground. And you’re positive that she’s up later than she should be, and has another full day of work ahead of her. But it’s difficult to deny her when she’s like this.

So you don’t.

**Author's Note:**

> [PurpleFictionMom](http://purplefictionmom.tumblr.com/) recently lamented the lack of Undyne/Reader fics on AO3, so I decided to oblige that pseudo-request! And major thanks to all of my other Discord friends who make stories like this possible.
> 
> Let me know what you think! And check out my other monster-sin in the Undertale: SINonymous series here on AO3. 
> 
> I take requests! [Prompt Guide](https://uwa-so-frisk.tumblr.com/post/167525355056/prompt-me-hello-hi-what-is-u-p-this-is-me)


End file.
